Draft load control for tractors



June 14, 1960 w. H. DU SHANE DRAFT LOAD CONTROL FOR TRACTORS OriginalFiled June 6, 1955 2 Sheets-Sheet 1 a un INVENTOR. W H DuSHANE June 14,1960 w. H. DU SHANE 2,940,530

DRAFT LOAD CONTROL FOR TRACTORS Original Filed June 6, 1955 2Sheets-Sheet 2 FIG. 7

6 O M 7 A g 0 m \r N 6 G 6 v. EH 9 n l 9 \7 8 F 0% =26 2-4 0 ID w AVL O9 O 6 88 O O 9 2 6 80 %H 4 2 O m 4 2 m 6 K 6 8 M 6? 7 MW l 6 I I W 6 w O2 2 2 W-6 4m. /6 OB\ M 6% 9 8X 0 7 4 2 9% O 5 7 4 M 8 G 5 l I 8 5 2 8 l0 II 8 O 2 2 8 2 0 i m l b 6 4 w 3 I P 2 2 .l 4 I B B .m N I o w w 6 I 7A a 3 T M \Qk .l u u 0 Ru 0 mm 6 United States. Patent r 2,940,530 4DRAFT LOAD comer. non morons Wallace H. Du Shane, Waterloo, Iowa,assignor,.by

mesne assignments, to Deere & Company, a corporation of DelawareContinuation of abandoned application Ser. No. 513,352, 1955. Thisapplication Apr. 16, 1958, Ser. No.

20 Claims. (Cl. 172-7) This invention relates to a draft control systemfor an agricultural tractor and features improvements in theconventional type of draft load control system in which the draft loadis balanced against a yielding means in the form of a compression springand which system includes a power adjusting mechanism actuated byvariations in draft load so as to adjust the working depth of theimplement so as to maintain a constant draft load.

This application is a continuation of copending application, Serial No.513,352, filed June 6, 1955, now abandoned.

A system of the general character referredto above is shown basically inthe US. patent to Ferguson 1,687,719, wherein variations in normal draftload operate mechanical means for adjusting the working depth of theimplement. In the recent past, hydraulic power means has beensubstituted for the mechanical means of the Ferguson patent, with theusual advantages attendant upon the use of hydraulic circuits. In thepresent: case, reference will he had to the improved systemas used withhydraulic control means, but such reference is representative only.

As further representative of the environment in which the inventionfinds particular utility, there isdisclosed here a tractor and plow, theplow being typical of an implement in which draft loads between thetractor and implement are caused to vary by such variables as soildensity, wheel slippage, etc. Balance of 'draft load or draft forces hasheretofore been achieved by the use of a coiled compression springoperating to resist compressive forces in a top link between the tractorand the implement. It has been found that a compression spring of thecharacter noted leaves much to be desired in the way of sensitivity andeconomy and according to the present invention the coil spring isreplaced by a simple bar adapted to be stressed in bending so that aportion thereof will be deflected and will be returned to normal inresponse to variations in draft load. The invention features the use ofa bar preferably disposed transverse to the line of advance and havingopposite end portions to which the lower draft links of the draft systemare pivotally connected. With this arrangement, tension in the lowerdraft links applies bending loads to the bar, and the bar is supportedon the tractor by spaced 'apart fulcra so that a midportion of the barwill deflect and will return to normal in response to variations in thebending stresses. A signal member is engaged by or at a midportion ofthe bar and picks up a signal as the bar deflects and returns to normal,this signal being transmitted in conventional fashion, if desired, tothe power adjusting means on the tractor, whereby such means isactivated or deactivated as the case may be so as to vary the workingdepth of the implement.

The invention features the provision of means fo varying the momentacting on the bar, whereby each of the draft links or its equivalentelement may be adjusted closer to or farther from'its associatedfulcrum. I Another object of the invention is to provide simple mountingPatented June 14, 1960 means for the bar which includes means forlimiting bending of the bar, means for preventing rotation of the barabout its axis, and adjustable spacer means for accommodating variationsin spacing of the draft link elements lengthwise of the bar. In amodified form of the invention, the principles are utilized inconjunction with the compressive forces in the top link of the draftconnection.

It has further been determined that in the use'of extremely longimplements, such as four-bottom plows, the draft linkage actuallyfunctions with compression in the lower links. According to the presentinvention, the deflection of the bar in bending accommodates thisphenomenon.

. The foregoing and other important objects and desirable featuresinherent in and encompassed by the invention will become apparent aspreferred embodiments of the invention are disclosed in detail in thefollowing specification and accompanying sheets of drawings, the severalfigures of which are described immediately below.

Fig. 1 is a fragmentary side elevational view of the rear portion of atractor and associated implement.

Fig. 2 is a schematic view, partly in section, showing the poweradjusting means, the actuating means therefor, the signal member and thebar in bending.

Fig. 3 is a fragmentary sectional view as seen substantially along theline 3-3 of Fig. 2.

. Fig. 4 is a view similar to Fig. 3' but showing a different spacingbetween the draft link elements.

Fig. 5 is an enlarged end elevational view as seen in the direction ofthe arrow bearing the encircled numeral 5 in Fig. 4.

Fig. 6 is a schematic view, partly in section, of that form of theinvention in which the bar is used in 'conjunction with the top link ofthe draft means.

Fig. 7 is a sectional view as seen on the line 7-7 of Fig. 6.

The environment chosen for the purposes of illustration includes atypical agricultural tractor having a forc and-aft body 10, the rearportion of which comprises a lubricant-containing housing 12 havingopposite laterally spaced apart upright side walls 14 and 16 from eachof which extends a laterally outwardly projecting axle for mounting atraction wheel. The right-hand axle appears at 18 and the left-handtraction wheel appears at 19 in Fig. '1. The expressions right-hand andlefthand" are used with reference to the position of an observerstanding behind the tractor and looking forwardly.

The tractor includes as a component part thereof a power-adjusting'means20 (Fig. 2) the basic components of which are contained in a secondaryhousing 22 in which is journaled a transverse rock shaft 24. Theinterior of the secondary housing 22 includes a cylinder 26 whithinwhich is a piston 28 that is rod-connected at 30 to an interior arm 32fixed to the rock shaft 24. A pair of external arms, only one of whichappears at 34, are secured respectively to opposite outer ends of therock shaft 24. Each lift arm 34 is connected by a lift link 36 to alower draft link element 38, which element is part of draft meansincluding a second lower draft link element 40 and a single top link 42for effecting a draft connection between the tractor and a trailingimplement, which implement is shown here as comprising a plow having aframe 44 and a pair of plow bottoms 46.

Each lowei draft link is pivotally connected on a transverse axis at 48to the plow beam 44 and the plow has a rigid mast 50 to the upper end ofwhich a pivotal connection is efiected at 52 with the rear end of thetop link 42. The forward end of the top link is, in that form of theinvention shown in Figs. 1 through 5, pivotally connected at 54 to arear part of the tractor housing 12. The forward ends of the draft links38 and 40 are respectively apertured in transverse alinement at 56iallied' componcnts'to. be presently described, afiords support for thebar 60. As best shown'in Figs. 3 and 4,

rections normal to the length ofthe bar' 60. Thesl'ot and '53 (Figs. 3and 4) for pivotal connection tea' low- 7 control means for effectingactivation and deactivation o the power adjusting means 20, whichdetails will be,

tain to the mounting of the bar 20. onthe tractor.

Therear' part of the tractor body housing '12, and:

the side walls 14 and 16" are respectively vaperturedin.

i brought out below. The present description will peralinement at 62 and64, the apertured portions of the V side walls serving as fulcra beyondwhich end portions 66 and 68, respectively, of the bar project laterallyoutwardly, a midportion 70 of the'bar being, of course, dis.- posedbetween the fulcra '62 and 64. The apertures62 and 64 are shaped asshown to permit deflection 'ofthe barwhen the bar'is' stressed inbending, which will occur when draft -=loads are applied to the bar viathe draft link elements 38 and 40. Since the housing 12 is adaptedtocontain lubricant for the final drive mechanism (not shown) of thetractor, the apertures 62"and 64 respectively contain lubricant andcontaminant seals '12 and 74. t

"The right-hand'sidewall '14 carries. an external bracket.76, which isrernovably afiixed to the side wall: as by cap-screws 78; This bracket.includes a portion 80 in transverse .alinement with the end portion 660f the 'bar 6tl'and spaced laterally outwardly from the proximate sidewall 14 so asto afi'ord a space within which the bymeans-ere sphericalmember 82 on the bar '60. The space between the bracket portion 80 andthe side wall spacer means 8 4 and a pairof thrust washers 86'.

The outer bracket portion 80 thus confines the assembly, 82-84-8;6,'together with the front end of the draft link against axialdisplacement; in additionto that, the portion 80 serves two otherfunctions For. the' first; of; these, the portion 80 has therein a shit83: elongated in a fore-and-aft direction, orin opposite 1diis closed atopposite endsand' therefore, 'aflords stop means limiting bending ofthe'en'd portion 66, ofthe, bar either a, rearwardly or a" forwardlydirection. f The other function of'the portion 80 evolves from theprlo vsi h rein of a f ior'e 'n -ai gr o 90 whi h; recei ye a-lock f p n 2' gs e diametrically through. he bar apertu'red front end 56 or the draftlink 38 'is received" by the tractor body housing 12. v I V The forwardapertured end 58 of the left hand draft link 40 includes a sphericalmember 106 with which are cooperatively related a pair of thrust washers108 and aspacer means 110. V

'Figs. 3 and 4 illustrate 'that'the lateralspacing between the draftLink elements 38, andfitflmayibe varied by interchang ing the positions,of the spacers 8ft andllll. This mportant from the standpoint ofutilizing different implements"with-thesame tractor. For example, in'Slbrne implements, it is necessary that draft links corresponding tothose at 38 and :bespaced-farther-apart-at some times than' at others.interchangeabilit of the "spacer means positions may be readilyaccomplished as,':for example, by removing the cap screws 78 ;and 96 toinitiate the removal of the brackets and interchanging procedure, afterwhich the parts may be restored to normal positions, the -o nlydiflerence-beingfthat-in one case the spacers will be inwardlpofthedrafelink balls. and in the other case the spacers will 'be outwardly of thedraft link balls. Since draft: loads-:appliedfto the bar 60' to. stressthe bar in bending appliedire'spectively at the outer end portions66and' 68, the moment at each side oi thern'idportion willyof course,be-varied according to the axial distancev between the midpoint and theconnection of the draft links 38'and 40'." The taperedshapes ofthe-apertures 62 and '64 permit rearward'defiection, for example, of theouter end portions, accompanied by forward deflection of the midportion7|) of the bar, which will occur inthe event of the application oftensional forces or loads to the draft links. In those cases in whichcompression loads are applied to the draft links, the outer end portions6.6 and'68. of the-bar will be deflected fore d, por ion 66-. Cc n atcn' between. the pin; 92 an the groove 94) Iafiords means for preventingangular} movement of the bar 60 about its which-is important inmaintainingthe axis of the bar, since it is a pracr tical impossibility'to. manufacture or otherwise maintain the bar true to its own axis, Thegroove 9tiris preferably made, as; long as it, is shown so that. the pin92. may be driven; out in either directionffpr etl 'ecting removal ofthe bar.

The opposite wall 16 carries thereon: abracket '94 which is symmetricalas respects'thebracket 76. screws 96 serve tohold the bracket 94' in'place'andflan dates a b rrcarried diam tn'calpin 0.4.- for assistin fpreventing angular movement; of the bar: about its axis, as l ascc psraing; with the-pin; 91in: holding the axial-i ,wardlyand the midpor'tionwill consequentlybe'de flected' rearwardly; Of course, the inherentlyresilient bar is capable. of deflection: and of returning 'toits' normalposition. The bar is designed for little or no deflection underlighter-normal dr-aftloads, but isadequately sensitive for the purposesdesired, as will be brought'out below.

a The signal: picked up tr'om tar transmitted by" the deflection andireturn to-normal 'of ther 'midportion 70 of the bar 60 is used tocontrol the "power adjusting means '20 through the medium of actuatingmeans 112'. This means'coinprises a valve housing Ha'included in. or aspart of 'eitherlthetractor-housing 12 or theiauxiliary housing 22; Asshown schematically in Fig; '2, the hens 1'14 has an ihternalchamber116' connected to thecylinder 26' by a conduit 1-18 and controlled byaahighpressure poppet valve-120 and an exhaust poppetvalve "122forrespectively controlling a supply line1 24 from a: pump 126 and anexhaust erreservoi-r line 123. The poppet; valves arerespectivelyspringfloaded to normal closed positions to hydraulicallylockthe cylinder 26. The fluid pressure system as shown is of theconstant pressure type, but any other type could be employed.

' A- valve controlling member-130 is pivoted-at -1-32 to V the v'atvehousing 114 andengages' -the stems of the-poppet valves 120 and 1622.Rocking ofthe member 1-30 in one direct-ionwill open one'valve while theother-valve remains closed: Contra of t-he member 130 is effected byalinlt3132" that is =pivotally-connected intermediate the ends of alever'1-34. Theu'pper end of this lever is. tpivotallyconnected' at 136 to alink 133' that extends forwardly to a hand cont-rol Fever 140; The, handlever isfulcrumed at 1'42fi'en' aconvenient portion of these:-

I ondary housing22*and5hasassociatedtherewitha conventionalarc'uately"slotted sector-'14 l; Asfis typical of arrangementsofthist-y'pe, --thereis sufiicient friction between the hand lever 1340and; the 'sectonl M to maintain any'selected position of'the 'handlever:

The transmission gof signals from the barrio. m. the actuatingmeans 11-2 is eif ected by a signal member146', fulcruined ihterrnediate itsends at 148 w, a suitable sup- Operation (Figs. 15)

As seen in Fig. 2, both poppet valves 120 and 122 are closed. Hence, thehydraulic system is locked and the position of the rock shaft 24 isfixed. Since the draft linkage 38-40-42 is connected to the rock shaft24 via the arms 34, the position of the implement will be fixed. When itis desired to lower the implement into the ground, the hand lever 140 ismoved forwardly, exerting a tensional force through the link 138 .on theupper end of the lever 134. During this phase of the operation, thesignal member 146 will be fixed; hence, the pivot at 156 will be thefulcrum for forward or clockwise swinging of the lever 134. Thismovement of the lever 134 causes a forward pull on the link 132',resulting in rocking of the valve-operating member 130 about its pivot132, causing the exhaust poppet valve 122 to be lifted from its seat inthe valve chamber 116. Thereupon, fluid may flow from the cylinder 26 tothe exhaust line.128 via the line 118 and chamber 116.

As the tractor and implement move forwardly, the plow bottoms 46 willenter the ground and ultimately impose on the tractor via the draftlinks 38 and 40 a draft force that will be balanced against theinherently resilient bar 69. If it be assumed that the draft force ismeasured in tensional load, there will be a rearwardly applied forceacting through the draft links 38 and 40 onto the outer ends 66 and 68of the bar 60, causing the midportion 76 of the bar to be deflectedforwardly. As this forward deflection occurs, the spring 154 causes thesignal member to pivot in a counterclockwise direction, therebyeffecting clockwise swinging of the lever 134 about the pivot 136 as afulcrum, since the position of the hand lever 140 is fixed. This actionreverses the previous movement of the valve operator 130 through thelink 132', restoring the valve operator to its original position andallowing the exhaust check valve 122 to be returned to its closedposition by its closing spring. The system is again hydraulically lockedand will remain so as long as the draft force remains normal or untilthe position of the hand lever 148 is changed, all in accordance withtheusual operation of a system of this character. In the event that thedraft force exceeds the normal value, the midportion 7 of the bar 69will be deflected farther forwardly, causing further counterclockwiseswinging of the signal member 146, resulting in opening of the highpressure poppet valve 129 and the consequent supply of fluid underpressure to the cylinder 26, efiecting forward movement of the piston 28and clockwise rocking of the rockshaft 24 to raise the implement to anew operating depth. As will be seen, in the event that the forces inthe draft links 38 and 44 are in compression rather than in tension, theouter ends 66 and 68 of the bar 69 will be deflected for: wardly,causing a rearward deflection of the midportion 70 of the bar. This willbe followed by clockwise swinging of the signal member 146 andcounterclockwise swinging of the lever 134 about the pivot 136 as afulcrum. This action results in opening the exhaust poppet valve 122 topermit the exhaust of fluid from the cylinder 26 so that the implementmay assume a deeper working posi tion.

One of the principal advantages of the bar 60, which is stressed inbending as already described, is that it is extremely economical.Moreover, it measures the draft force in both draft links 38 and 40,being capable of measuring a plus value in one and a minus value in theother, as well as plus or minus values in both. Although the bar isadequately sensitive to normal varia tions in draft load, it is capableof accepting shok loads without causing the signal member 146 torespond, since the bar 60 is readily capable of returning to its normalposition rather quickly. The bar is preferably of highcarbon steel, withcarbon in' the 30-90% range.

The rear ends of the slots 88 and 100, respectively in the outer orexternal brackets 76 and 94, limit rearward deflection of the respectiveouter end portions. These are designed to be contacted by the endportions of the bar under maximum draft load. Shock loading of theimplement thereafter'will have no further effect on bend; ing of the bar60. The same is true in a more limited sense when the draft links 38 and40 are reflecting minus values, it being noted that the slots 88 and 110are elongated farther rearwardly than they are forwardly.

Figs. 6 and 7 In this form of the invention, the principles previouslyvdescribed are utilized in connection with a top link element 42a, thelower draft links 38 and 40 being simply pivoted to the tractor bodyhousing 12 as by a transverse pivot 158. Other components of thetractor, such as the power'adjusting means 20 and the actuating means112 exist as previously described.

The tractor body housing 12 rigidly carries at a rear upper portionthereof a support 12a for supporting an elongated inherently resilientbar 60a that is similar in all respects to the bar 60previouslydescribed. For the purposes of convenience, the same referencecharacters, suflixed by the letter a will be used. To this end, thesupport 12!: has laterally spaced apart portions 14a, and 16:: that arerespectively apertured at 62a and 64a, plus outer portions 80a and 980that respectively have elongated slots 88a and a. Pin and groove means92a- 90a and 1G4a-102a prevent angular movement of the bar 60a. The barhas oppositeouter end portions 66:: and 68a as well as a midportion 70a.The support portions 14a and 80a are spaced apart to receive aright-hand laterally offset leg 38a of the top link 420. This top linkhas an offset left-hand leg 40a received between the support portions16a and 98a. Consequently, the top link is adapted to apply draft loadsto the bar 60a to stress the bar in bending, the midportion of thebarrbeing de flected and cooperative with a signal member. 146a that isin constant engagement therewith. The signal memher is pivoted at 148aon, a suitable external bracket 150a and is biased by a spring 154a intoengagement with the rear side of the bar 6011. A link 1560 extendsforwardly from the upper portion of the signal member 146a and has apivotal connection at 156k with the leverl134. Also recognizable in Fig.6 are the va'lve operator and as will be operational characteristicsthereof. Hence, it- 1 is deemed that further description is unnecessary.

The advantages of the bar 60 applyalso' to thef bari Various otherfeatures of the invention, not categori cally enumerated herein, willundoubtedly occur to those skilled in the art, as will manymodifications and alterations in the preferred forms of the inventionshown, all of which may be achieved without departing from the spiritand scope of the invention. i

What is claimed is:

1. For a tractor having power adjusting means for effecting theadjustment of an associated implement and ac tuating means forselectively activating and deactivating the power adjusting means:draftload control means comprising a support on the tractor; aninherently resilient bar carried by the support for temporary deflectionfrom normal when stressed in bending; a movable signal mem; beroperatively connected to the actuatingmeansand engaging the bar; andimplement-connectible draft means connected to the bar for stressingthebar in:be nding, in response to' implement draft. loads soLas.to;defl'e.ct the ,the end portion "of' l '1 '1 "definedin claim "7,-includingz 'means -eng'agedfb v'e' i proximate" stop me 1 merit ofthebar about its axis."

aneoeso bar; and incur movement of'the signaLmemberand con- I 'tivati'onof the power adjusting means.

equent a 7 means: carried my the: tractorand normally spaced fromthebar" and engageablei bycthe bar. under bending loads forlimitingdefiection of'the bar.

' yielding means in the draft connection and acting against the draft iand balancingth'e normal 'draft," power. lift means on the r tractor forregulating the working depth of the impleme'nhand actuating means forthe power lift means actuated by relative movement between their'n'plernent' and tractor in a fore-and-aft direction in response tovariations in saidnormal draft to cause the power lift means to correctthe working'de'pth'of the implement,"characterizedin that the yieldingmeans comprises an inherently resilient" bar stressed in bending byyariatioiisjin said normal dr'aft.

fe sit he adjustment'bf an associated implement' and actuating means 7for selectively V activating and deactivatmpri'sing'"'an elongatedinherently "resilient bar having The mvention "defined in claim: 1",includingz-jstop receiving slot elongated inf a direction parallel 'to'defiec- .Fon {tractor haying power adjusting means'FfOr cf- Q" r r r Vsecreted implemenL'and actuating means disposed be- V elongatedinherently resilient bar positioned with its length transverseto-thetractor housing "and the housing side walls'be'ingfaperturedini'transverse' alirrement to receive the bar; said bar haying oppositeend portions "projecting laterally respectively 'beyondi'the:side walls'and? a midportion betweenj'said sidewalls, said side'walls'respectively' alfordingwpaced fulcra -for' the bar' so that implementloadsapplie'dto the endportionsof the bar -in directions transverse to thelength of'the'bar willstress the bar in'bending lto cause: temporarydeflection of the midportion of: thesbar; -amovable signal membersupported within-the housing and operativ'ely connectedto thetactuatingz means, saidssignalmember engaging: the midportionsofithe barto be movedby said midportion upon deflectionsthereof; and.implement-connectibleidraft means", externally of. itheehou'singi andhaving a; pairr of laterallyspaceddraftdoad-responsiye elementsrespectively engaging the endportions of the barffor stressing. :the

bar-rm bendingso as. todeflect the r'nidportionr of the bar and incurmovement ofthefsignal member andrconsequent activation of the poweradjusting means.

' 1'2.The invention defined, in ,claim' 11, including: a pair erexternal brackets, one secured to eachfside wall in laterallyoutwardly'spaced'relationthereto and 'alined with the respectiveend'portion ofthe bar and confining th proximate draft' means elementagainst-displacement s lengthwise of the bar.

'g the ower adjusting means: draft load control mea'ns opposite end"portions "and a midportion; a support 7 i'nountin'g the'bar on the'tractor,"including a pair of f fulcra' spaced/apart 1lengthwiseof thebar and-engaging 1 V the barf respectively short of "its end portions sothat implement loads applied to the end portions ofthe bar in directionstransverseito the length of the bar will stress theb'ar in bending tocausetemporary -deflection'of the I a' signal imember operatively,

cofinectedto theactuating means and engaging the mj'dporn n rofjthe'barto be moved by lsa id-midp rtiOn upon deflections thereof; andimplement-connectibler"dfaft means: having a 'pair-Tof bar-engagingelements spaced 7 apart lengthwise of and rejspectiveljfi'engaging theend "b'arffor stressing :the bar in bending in {loads so" as tojdefl'ect said midportion ement' fofthe signal member and some: n"ofjthefpower. adjusting r'neahs L 7; rue, in entionfdefined in claim-6;; n ludi'ngz 'a pair idly of the fulcra and engage'able r respectivelywith thefbar to limit bending ofithe bar. 8. The in stop m "sin Qtheform of'anfear 'hayingltherein a sl'otri eeeiving elongated infthedirection of movem en of the fproxfiinate "end portion, said 'slot beingclosed afopposit'e'ends tto'aifdrd spaced stops limitingb'ending havinga rear housing-including hit- -and-& actuating means zdisposed beton-selectively: activating and dc:

iitiva ting the jpower adjusting means? the combination momm es; dr f-gilqadcontrol means comprising one end; plortionjfof' the bar iand thember' fofipreventing angular 'move- V fstop 'rnernb rs'fZori the supportspaced respectively out- 13. Foratractonhavinga rear 'housingincluding'late ierally spaced opposite sidewalls and carrying a poweradjusting means for ef'fectingthe adjustment of an asfp'o'rtion betweensaid "side walls, said side walls respectively 'aifording spac'edlfulcra for the bar so that' impleme'nt loads applied to the, endportions of the bar in directions transverse to the length of the barwill stress the bar in bending to cause temporary deflection ofthernidpor'tion' of the bar; a movable signal member supported within thehousing and operatively connected to the'actuating means, saidsignal'member engagingjthe midportion of the bar'to be moved by saidmidportion upon deflection thereof; ;implementconnectible jdraft meansexternally of the housing and includingla pair'of laterally spaced apartelements respectivelyapertured in transversefalinement to respectivelyhe received bythe bar. end portions;- and a pair bf external brackets,one

The invention defined, in in which: each ans "element andjtlie proximatefulcrum secured to: eachiside wall-in laterally outwardly spacedrelatiomthereto and in alinementwith ;the bar, each arse means elementbeing received between the respecitivel side wall and'bracket.

l l4..flfheinventionldefined in claim 13, in which: the draft fmeanselements are laterally adjustable relative to each. other to enablevariations in the lateral spacing therebetweem'each end portion' of thebar is'sufiiciently "long and each. bracketis spaced outwardly from therespective sidewall aesiifiicient distance-to accommodate variationsinspacing hewveen said elements;'and each end portion'offthe. bar hasspacer means selectively positionablehetween therrespective side wall'and draft means elementor between the respective bracket and'element tomaintain the selected spacing between the elements.

15. For a tractor having a lubricant-containing rear housing includinglaterallyrspaced opposite side walls and carrying a power adjustingmeans for effecting the 'adjustment'of anassociatedimplement, andactuating means disposed between. the sidel walls for'selectivelyactivat ing and deactivatingithe power adjustingmeanszithecombination therewithiofrdraft load control means comprisingmelongatedl inherently resilient bar positioned with its 1 lengthtransverse to the tractor housing each side wall having an aperturetherein and said apertures being in transverse alinement to receive thebar, said bar having opposite end portions projecting laterallyrespectively beyond the side walls and a midportion between said sidewalls, said side walls respectively afiording spaced fulcra for the barso that implement loads applied to the end portions of the bar indirections transverse to the length of the bar will stress the bar inbending to cause temporary deflection of the midportien of the bar; alubricant seal in each aperture and encircling the proximate portion ofthe bar; a movable signal member supported within the housing andoperatively connected to the actuating means, said signal memberengaging the midportion of the bar to be moved by said midportion upondeflection thereof; and implement-connectible draft means externally ofthe housing and having a pair of laterally spaced draftload-responsiveelements respectively engaging the end portions of the bar for stressingthe bar in bending so as to deflect the midportion of the bar and incurmovement of the signal member and consequent activation of the poweradjusting means.

16. For a tractor having power adjusting means for elfecting theadjustment of an associated implement and actuating means forselectively activating and deactivating the power adjusting means: draftload control means comprising a pair or" supports on the tractor andspaced apart transversely to the -fore-and-aft centerline of thetractor; elongated resilient means disposed transversely to saidcenterline and having opposite end portions carried respectively by saidsupports and further having an intermediate portion between saidsupports; a movable signal member operatively connected to the actuatingmeans and engageable with the intermediate portion of the resilientmeans; and implement-connectible draft means connected to the endportions of said resilient means for deflecting said end portions in onedirection transverse to the length of said resilient means and therebyto incur deflection of said intermediate portion in the oppositedirection.

17. For a tractor having power adjusting means for effecting theadjustment of an associated implement and actuating means forselectively activating and deactivating the power adjusting means: draftload control means comprising fulcrum means on the tractor; meansoperative as a lever disposed transversely to the fore-and-aftcenterline of the tractor and fulcrumed on said fulcrum means, saidlever means having first and second portions respectively at oppositesides of said fulcrum means; said lever means including means yieldinglyresisting deflection of said first and second portions respectively inopposite directions; a movable signal member operatively connected tothe actuating means and engageable with the first portion of the levermeans; and implementconnectible draft means connected to the secondportion of said lever means for deflecting said second portion in onedirection transverse to the length of said lever means and thereby toincur deflection of said' first portion in the opposite direction.

18. For a tractor having power adjusting means for an associatedimplement and actuating means for activating and deactivating the poweradjusting means: draft means comprising an elongated inherentlyresilient beam having opposite-implement-connectible end portionsreceivable of draft load from an implement; support means mounting thebeam on the tractor and including a pair of tractor-carried fulcrumelements spaced apart lengthwise of the beam and normally engaging thebeam respectively at points of the beam end portions so that said endportions respectively overhang said points for deflection relative .tosaid points when the beam is stressed in bending by draft load appliedthereto; and signal means operative in response to such deflection andeffective on the actuating means to incur activation of the poweradjusting means.

19. For a tractor having power adjusting means for effecting theadjustment of an associated implement and actuating means forselectively activating and deactivating the power adjusting means; draftload control means comprising support means connected to the tractor; aninherently resilient bar connected to the support for te porarydeflection from normal when stressed in bending; implement-connectibledraft means connected to the bar for stressing .the bar in bending inresponse to implement draft loads so as to deflect the bar from normal;and signal means operative in response to deflection of the bar andeffective on the actuating means to incur activation of the poweradjusting means.

20. *For a tractor having power adjusting means for effecting theadjustment of an associated implement and actuating means forselectively activating and deactivating the power adjusting means; draftload control means comprising support means connected to the tractor; aninherently resilient bar connected to the support for te porarydeflection from normal when stressed by load applied thereto in spacedrelation to the suppont means; implement-connectible draft meansconnected to the bar for stressing the bar as aforesaid in response toimplement draft loads so as to deflect the bar from normal; and signalmeans operative in response to deflection of the bar and effective onthe actuating means to incur activation of the power adjusting means.

References Cited in the file of this patent UNITED STATES PATENTS2,724,314 Evans Nov. 22, 1955

